1. Technical Field
The present invention relates generally to an improved data processing system and in particular to execution of operating systems in a data processing system. Still more particularly, the present invention relates to a method and apparatus for concurrent execution of operating systems within a data processing system.
2. Description of the Related Art
Virtual machine system (VMS) 100 is one architecture that makes it possible to apparently run simultaneously a number of operating systems (OS) on base machine (BM) 102, as illustrated in FIG. 1. A specific control program, such as virtual machine monitor (VMM) 104 is employed to interface between operating systems 106, 108, and 110 in FIG. 1. Instead of directly employing a base machine interface between base machine 102 and operating systems 106, 108, and 110, interface 112 is the interface between virtual machine monitor 104 and base machine 102. Interfaces 114, 116, and 118, also referred to as virtual machines, provide interfaces between operating systems 106, 108, and 110 and virtual machine monitor 104. Virtual machine monitor 104 provides interfaces 114, 116, and 118 to allow operating systems 106, 108, and 110 to appear to operate simultaneously. In reality, virtual machine monitor 104 provides a multiplexer function to correctly direct data flow between base machine 102 and operating systems 106, 108, and 110. In FIG. 1, three operating systems are illustrated, but any arbitrary number of operating systems may be employed.
Operating systems 106, 108, and 110 each execute a number of tasks. In the depicted example, operating system 106 executes tasks 120, 122, and 124 while operating system 108 executes tasks 126, 128, and 130. Operating system 110 executes tasks 132, 134, and 136. In this manner, virtual machine system 100 allows a number of operating systems to appear to execute simultaneously on a single base machine. Virtual machine system 100 requires all computer software to be written to the same base machine interface.
In FIG. 1B, a known system for executing personal computer applications on another operating system is illustrated. Data processing system 140 includes a base machine 142, which is connected to an interface 144. Operating system 146 communicates with base machine 142 through interface 144. Native task 148 and 150 are executing an operating system 146. Additionally, personal computer (PC) emulator 152 also is executing within operating system 146 as a native task. PC emulator 152 emulate the central processing unit (CPU) and peripherals of a personal computer. In addition, interface 154 is provided to aid in emulating the entire PC to allow PC operating system 156 to run. In this manner, PC task 158 may be executed within data processing system 140 even though data processing system 140 is configured to normally execute data processing system 146.
Turning now to FIG. 1C, a block diagram of a known system for executing UNIX applications along with PC applications is illustrated. Data processing system 160 contains a base machine with an interface 164 to PC operating system 166, which has PC task 168 and 170 executing within it. Additionally, UNIX emulator 172 is executing within operating system 166. Interface 174 is provided to execute UNIX task 176 within data processing system 160. Such a system allows for UNIX applications to execute along with PC applications on a PC compatible data processing system.
This and other types of architectures employed to allow for execution for multiple operating systems depend on the emulation of one environment or the other. Such emulations can lead to significant performance losses and incapabilities. Therefore, it would be advantageous to have an improved method and apparatus for concurrently executing multiple operating systems.